稀土萃取分离技术方法研究

稀土在工业诸多领域中发挥着关键作用,在增材制造材料和介电材料等高新技术领域均显示出可期的应用前景。稀土元素的分离是衔接稀土资源与高性能稀土功能材料的关键过程,所以高效提纯稀土元素变得尤为重要。本文梳理了化学沉淀法、离子交换与吸附法、萃取色层法、溶剂萃取法、液膜分离法这些经典方法和化学气相传输法、氧化还原法、萃取沉淀法、微生物法、非平衡溶剂萃取法这些新技术方法的优缺点和适用性,侧重分析了这些技术方法在节能减排方面的最新研究情况,并展望了稀土分离提纯领域的重点发展方向,以期为稀土资源的绿色高效开发利用提供依据和借鉴。     

Speciation of oxidation states of elements by capillary electrophoresis

Progress made in the last five years in the application of capillary electrophoresis methods to chemical speciation of elements is reported on the basis of over 100 literature references. The main trends observed include development of new on‐ and off‐capillary derivatization methods, application of new detection methods, and especially coupling of CE separation systems to powerful atomic spectroscopy and mass spectrometry instruments with various ionization techniques, providing either a sensitive element‐specific detection method or a third dimension for high performance separation. Besides numerous CZE and MEKC capillary electrophoresis methods only very few examples of CE speciation with capillary electrochromatography can be found. Concerning the chemical forms of elements determined, the new procedures developed are mostly focused on redox speciation of various oxidation states of elements, metal‐bound high molecular compounds, and organometallic species.     

毛细管区带电泳对羟基苯甲酸三种异构体的分离研究

考察了邻羟基苯甲酸、间羟基苯甲酸和对羟基苯甲酸在毛细管区带电泳分离时的行为。研究了缓冲液pH、浓度和分离电压对三种羟基苯甲酸异构体分离的影响,结果表明在10 mmol/L Na2HPO4缓冲体系(pH 10.15),运行电压25kV,实验温度25℃的分离条件下,采取压力进样(3.4 kPa×3 s),检测波长210nm;3种异构体在7 min内获得基线分离。邻羟基苯甲酸、间羟基苯甲酸、对羟基苯甲酸在2~100μg/mL范围内,峰面积与质量浓度具有较好的线性关系,检出限分别是0.96,1.27和1.07μg/mL。     

混合稀土离子的毛细管电泳电导法分离检测

采用高效毛细管电泳电导检测法分离检测了稀土离子。以醋酸-醋酸钠为背景电解质,4-吗啉乙磺酸（MES）为络合剂,在24kV的高压下,7种稀土离子得到子较好的分离。考察了背景电解质的pH和浓度,络合剂的浓度,分离电压等对稀土离子分离的影响。在选定的实验条件下,7种烯土离子在10min内守成分离检测。     

Optimization of preparative chromatographic separation of multiple rare earth elements

This work presents a method to optimize multi-product chromatographic systems with multiple objective functions. The system studied is a neodymium, samarium, europium, gadolinium mixture separated in an ion exchange chromatography step. A homogeneous Langmuir Mobile Phase Modified model is calibrated to fit the experiments, and then used to perform the optimization task. For the optimization a multi-objective Differential Evolution algorithm was used, with weighting based on relative value of the components to find optimal operation points along the Pareto front. The objectives of the Pareto front are weighted productivity and weighted yield with purity as an equality constraint. A prioritizing scheme based on relative values is applied for determining the pooling order. A simple rule of thumb for pooling strategy selection is presented. The multi-objective optimization gives a Pareto front which shows the rule of thumb, as a gap in one of the objective functions.     

离子色谱非梯度洗脱法同时测定7种稀土元素的研究

研究了离子色谱非梯度洗脱法同时测定7种稀土元素的方法,用草酸一元淋洗液,采用非梯度洗脱方式,以PAR为显色荆,在520nm处对7种稀土元素同时进行检测。考察了淋洗液的组成、浓度、pH及流量等因素对被测组分分离和测定的影响,选择了显色剂的浓度、流量和检测波长,并进行了干扰实验,在选定的最佳分离测定条件下,测定了7种稀土元素的线性回归方程、检出限0．04～0．20mg／L,回收率在94．3％～101．5％之间。本方法已用于稀土氧化物的高温氯化产物中稀土元素的测定。     

ICP-MS同时测定植物性食品中稀土元素的方法研究

建立了植物性食品中16种稀土杂质(Sc、Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu)元素的电感耦合等离子体质谱(ICP-MS)的分析方法.考察了基体效应及质谱干扰,应用In内标,有效地补偿基体效应所引起的测量偏差,建立修正公式校正质谱干扰.对照分析了参考标准物质.对所测定元素,校正曲线的相关系数为＞0.9990,方法的检出限低于2.2 pg/g(Sc为95pg/g),回收率为92%～106%,RSD优于3.2%(n=7).     

毛细管区带电泳法拆分手性药物环扁桃酯

近年来,随着不同种类的手性添加剂[1]在毛细管电泳(CZE)中的使用,毛细管电泳越来越显示出其强有力的手性拆分性能。具有特殊笼状结构并含有多个手性中心的环糊精及其衍生物是毛细电泳手性分离研究中最常采用的手性添加添[2-4]。本文合成了环糊精衍生物单3 O 苯基胺甲酰基 β CD[2]并以之作为手性选择剂分离了β CD及手性药物环扁桃酯。1　实验部分932 3 HVPS高压电源(山东省化工研究院),DD 2000型可调波长紫外检测器(中国科学院大连化学物理研究所),XWT型记录仪(上海大华仪表厂),pHS 25型酸度计(上海雷磁仪器厂),石英毛细管45cm…     

A quick method for the simultaneous determination of ascorbic acid and sorbic acid in fruit juices by capillary zone electrophoresis

A method of quickly determining ascorbic acid and sorbic acid by capillary zone electrophoresis with ultraviolet detection was developed. The choice of background electrolyte, wavelength, injection time and applied voltage were discussed. Ascorbic acid and sorbic acid were well separated in 80 mmol L⁻¹ boric acid-5 mmol L⁻¹borax (pH = 8.0) in 5 min at the detecting wavelength of 270 nm. Under the optimum condition, the method has linear ranges of 2.54-352.00 mg L⁻¹ for ascorbic acid and 1.08-336.39 mg L⁻¹ for sorbic acid with the detection limit of 1.70 mg L⁻¹ for ascorbic acid and 0.54 mg L⁻¹ for sorbic acid, respectively. Other organic acids in fruit juices have no effect on the detection. This method is very feasible and simple and can be used to detect ascorbic acid and sorbic acid in fruit juices.     

Prediction of the separation of phenols by capillary zone electrophoresis

The effect of pH and ionic strength on the migration of neutral acids in capillary zone electrophoresis (CZE) has been studied for several phenols. The mobilities of the phenols and the efficiency of the capillary have been related to the studied factors. The mobility can be related to the pH of the running buffer through the mobility of the phenolate ion, and the conditional acidity pK value of the phenol at the working ionic strength. This allows prediction of the migration of the phenol, solely from its pK_a^′ value (literature pK_a corrected for the ionic strength of the solution) and mobility of the anion, which can be easily calculated from the mobility at a basic pH value and the pK_a^′ value. Combination of the predicted mobility with the efficiency allows estimation of the resolution of the consecutive peaks obtained for a mixture of phenols. This method has been tested for two groups of phenols of environmental interest.     

Size separation of silica nanospheres by means of capillary zone electrophoresis

The electrophoretic mobility of silica nanospheres was shown to be a function of separation conditions such as pH and phosphate concentration of a carrier electrolyte. The separation selectivity can be controlled by the separation conditions and optimised depending on the sample composition. The effects of pH and phosphate concentration of buffer solutions on the nanosphere electrophoretic mobility are explained using the Overbeek-Booth electrokinetic theory taking into account both electrophoretic retardation and the relaxation effect.     

有机改性剂对氯代酚毛细管区带电泳分离的影响

在分离19种氯代酚的过程中,考察了不同的有机添加剂对其毛细管区带电泳分离的影响,发现除了缓冲溶液的pH值外,缓冲溶液添加剂对氯代酚的电泳分离也有较大影响。这种影响与添加剂和氯代酚形成氢键的能力有关。     

Separation and simultaneous determination of quinolone antibiotics by capillary zone electrophoresis

Summary The potential of capillary zone electrophoresis has been investigated for the separation and quantitative determination of some quinolone antibiotics. The influence of different conditions, such as the nature and concentration of the electrophoretic electrolyte, on migration time, peak symmetry, efficiency and resolution was studied. A buffer consisting of 100mm HEPES adjusted to pH 8.5 containing 10% (v/v) acetonitrile was found to furnish a very efficient and stable electrophoretic system for the separation of exoxacin, ciprofloxacin, ofloxacin, oxolinic acid, nalidixic acid and pipemedic acid. A linear relationship between concentration and peak area for each compound was obtained in the concentration range 0.25–40 μg mL⁻¹; detection limits were approximately 0.25 ng mL⁻¹. It was demonstrated that the method can be used for the simultaneous determination of these six antibiotics in serum and urine samples.     

Analysis of formic and acetic acid in rain water by capillary electrophoresis

A simple technique is described for the routine capillary electrophoretic determination of formic and acetic acid in rain water. These acids were determined simultaneously in approximately 6 min using a carrier electrolyte containing lO mM phosphate and 0.5 mM myristyltrimethylammonium bromide (MTAB) as electroosmotic flow (EOF) modifier at pH 6.5 and direct UV detection at 185nm. The method is quantitative, with recoveries in the 99-101% range and linear up to 5mgL^-1. The precision is better than 2.1% and the procedure shows the appropriate sensitivity, with detection limits between 0.042 and 0.055mg L^-1. The proposed method was successfully employed for the determination of formic and acetic acid in 57 rain water samples, collected from October 2000 to February 2001 in four different sampling stations located in Galicia (NW Spain), by direct sample injection after filtration.     

Mechanism of sequence-based separation of single-stranded DNA in capillary zone electrophoresis

Separation of DNA by length using CGE is a mature field. Separation of DNA by sequence, in contrast, is a more difficult problem. Existing techniques generally rely upon changes in intrinsic or induced differences in conformation. Previous work in our group showed that sets of ssDNA of the same length differing in sequence by as little as a single base could be separated by CZE using simple buffers at high ionic strength. Here, we explore the basis of the separation using circular dichroism spectroscopy, fluorescence anisotropy, and small angle X-ray scattering. The results reveal sequence-dependent differences among the same length strands, but the trends in the differences are not correlated to the migration order of the strands in the CZE separation. They also indicate that the separation is based on intrinsic differences among the strands that do not change with increasing ionic strength; rather, increasing ionic strength has a greater effect on electroosmotic mobility in the normal direction than on electrophoretic mobility of the strands in the reverse direction. This increases the migration time of the strands in the normal direction, allowing more time for the same-length strands to be teased apart based on very small differences in the intrinsic properties of the strands of different sequence. Regression analysis was used to model the intrinsic differences among DNA strands in order to gain insight into the relationship between mobility and sequence that underlies the separation.     

茶叶中稀土元素的萃取分离-ICP-AES法测定

采用1-苯基-3-甲基-4-苯甲酰基-5-吡唑酮(PMBP)苯溶液萃取分离-ICP-AES法同时测定茶叶中15种稀土元素,消除了基体的干扰,并对样品前处理方法、萃取分离条件进行了考查.方法回收率为: 92.3%～112%,相对标准偏差＜2.5%.在最佳工作条件下,测定了茶叶标准物质(GBW07605)中稀土元素,结果与标准值吻合.     

毛细管区带电泳法测定粉针剂中头孢拉定的含量

用毛细管区带电泳法测定头孢拉定的含量 ,未涂层毛细管柱 (75 μm×48.5cm ,有效长度 40cm) ,电压 2 8kV ,检测波长 2 3 0nm ,温度 2 0℃ ,进样 5×1 0 3Pa× 3s。运行缓冲液为 2 5mmol/L硼砂缓冲液。方法的线性范围 3 1 .2 2μg/mL～ 749.2 8μg/mL ,检测限为 1 .1 7μg/mL。     

Pseudopotential study of the rare earth monohydrides,monoxides and monofluorides

Nonrelativistic and quasirelativistic energy-adjusted pseudopotentials for fixed 4f subconfigurations of the rare earth elements La through Lu together with corresponding optimized valence basis sets have been used in SCF and CI(SD) calculations to determine the spectroscopic constants for the energetically low lying superconfigurations of the lanthanide monohydrides, monoxides and monofluorides. The experimentally observed trends in dissociation energies, bond lengths and vibrational frequencies for the ground states of the calculated superconfigurations of the monoxides and monofluorides are well reproduced. The results for the monohydrides are mainly predictions.